1. Field of the Invention
The present invention relates to an optical data recording apparatus which records data on an optical recording medium, such as on an optical disk.
2. Description of the Related Art
According to such an apparatus, a light beam with a predetermined intensity irradiates a writable or erasable optical disk to record data thereon. The most serious problem for this type of apparatus is the overwriting of new data on those tracks which have data already recorded thereon. The main cause for such overwriting is improper tracking at the time of data recording.
A conventional measure to prevent overwriting is disclosed in Japanese Patent Disclosure No. 54-147006. The disclosed conventional apparatus has a circuit for searching for a non-recorded region while monitoring a reproduced signal at the time of data recording, and a gate for disabling a recording circuit even upon reception of a recording command unless a non-recorded region detection signal is present. Another similar apparatus, known in the art, writes a record-completion flag in a recorded region on the recording medium to thereby prevent overwriting (data destruction).
However, these conventional apparatuses for preventing overwriting do not properly function as the data recording density gets higher, so that overwriting cannot be completely prevented.